There are, of course, other advantages to single-sex schools. These might include reduced supposed distractions from the opposite gender, and a more empowering environment that can boost students’ confidence in pursuing subjects that are not traditionally seen as a natural fit for their gender.

It appears that girls in particular benefit from single-sex education, especially when it comes to choosing STEM subjects. A report by the Girls’ School Association found that students in girls-only schools are 2.6 times more likely than those in coed schools to take further maths as an A-level, and are also significantly more likely to take up biology, chemistry, physics and computer sciences. They are also more likely to be active in sports.

“Personally, I studied mathematics at the University of Cambridge and rowed for my college, where about 80 per cent of maths students and 70 per cent of rowers are male,” Yau recalls. “This sometimes felt intimidating, and it made me appreciate even more the support and encouragement I received in STEM subjects and sports activities at my single-sex schools, Marymount Secondary School in Hong Kong and Badminton School in the UK.”

In addition, a study by AQR International, which specialises in psychometric testing, found that “scores for girls at single-sex girls’ schools are, generally, higher when assessing confidence and emotional control/management, compared with girls in co-educational schools”.

The advantage of single-sex education for boys seems to be less conclusive. While the GSA report found that boys also appear to do better in single-sex schools, other studies have found that the benefits for boys are negligible.

There are, of course, some pointed disadvantages to single-sex schools. Bullying can be rife and more ruthless than in coed institutions, which can lead to poor mental health among students.

But arguably the most significant drawback of single-gender schools is the lack of social interaction with the opposite sex. This can make it challenging when students go into the real world, attending university or working in offices, while necessarily having all the tools for effective communication that their coed peers might.

“I went to an all-girls’ school in the 80s and we were actually prohibited from seeing boys, which made me very uncomfortable around boys for a long time,” notes Benny. “There is still a risk of this happening, especially in traditional local schools in Hong Kong.

However, proponents of single-sex education believe that this isn’t as significant a concern as it once was because many girls’ schools today have strong ties to boys’ schools, with the two often coming together for sports, extracurricular activities and, in some cases, specialised classes. “As long as the school is a good fit, it’s important to understand that, while the classroom is a single-sex environment, pupils should be mixing with the opposite gender in ECAs or socials,” Benny explains.

Still, supporters of co-education argue that these schools do a better job of preparing students for real life by helping them develop social confidence and dismantle gender stereotypes. Generally, coed schools enhance students’ social skills, and usually also offer a broader selection of extracurricular activities, giving students the ability to develop well-rounded interests.

This is perhaps, at least partly, why co-education has become increasingly popular. According to Jessica Yuen, founder and CEO of Specialist Education Advisory, numerous all-girls’ and boys’ schools in the UK and Australia have moved away from single-sex education in recent years. Many of these schools have turned coed, allowing students of either gender to enrol, or adopted the “diamond model”, where the school largely operates on a co-educational system but separates students between the ages of 11 and 16 by gender.

In 2023, one of England’s oldest public boys’ institutions, Westminster School, announced its intention to “go fully coed” from 2030. It had previously begun accepting girls for sixth form (the last two years of high school) in the 70s. The prestigious Winchester College for boys also has a coed sixth form. With these changes, there are now only four boys-only boarding schools left: Eton, Harrow, Radley and Tonbridge. While there are still around 800 single-sex schools operating in England, most of these are for girls.

In the UK, the move to co-education is largely because of legislation by the new Labour government that have increased schools’ operating costs, believes Benny. Yau agrees, disclosing that “the management teams of prestigious UK single-sex schools have confessed to us in one-on-one meetings that another important reason for switching to coed is because of the reduction of applications due to increase of VAT [on fees].”

So what factors should be taken into account when choosing between single-sex and coed schools? Family situations are important, of course. For example, it might be impractical to have siblings of different genders attend different schools. Or a young girl growing up with brothers might feel more comfortable in a coed setting. When looking for the most appropriate school, “parents should consider their own family values and understand the schools’ approach to learning”, Yau explains.

In the end, though, the choice between single-sex and coed schools comes down to the individual student. “Having spent 13 years in girls’ schools in both Hong Kong and the UK, and working in the education sector for over a decade, I definitely agree that boys and girls excel in different learning environments,” says Yau. “However, the most suitable type of school ultimately depends on [the student’s] individual personality, interests and future goals … There is no right or wrong answer,” she concludes.